By genuine loan companies (sic) i assume you mean firms that offer a competetive interest rate?
I think it would depend on what sort of state your credit file was in. Obviously the better your credit rating the better rate of interest a finance company would be prepared to give you.
If you're a homeowner and have equity in your property then that would probably be the cheapest way to borrow a lump sum, although your home is at risk if you do not... blah blah blah!
As for credit cards, i believe Capital One offer a credit card for people who have had "credit difficulties" in the past. Although i doubt you would be given a very large credit limit, probably about �500, or would you get a very good APR, probably around the 30% mark.